The present invention relates to an apparatus and a method for folding and tucking disposable diapers in their crotch regions inward as a contiguous diaper structure is fed in a machine direction.
Various processes for making pull-on diapers are well known, including a typical example as will be described below.
This typical process comprises the steps of forming a continuous laminate including a liquid-pervious continuous first web and a liquid-impervious continuous second web which run in a longitudinal direction of these webs and are overlaid each other and liquid-absorbent cores which are interposed between the webs so as to be aligned in the longitudinal direction of the webs at regular intervals, folding back the laminate along a longitudinal center line of the webs with the second web inside, joining the laminates overlaid each other in a heat-sealing line extending in the transverse direction of the webs between each pair of the liquid-absorbent cores adjacent to each other, cutting out the laminate along respective first cutting lines each being convex toward the longitudinal direction to form leg-holes and finally cutting the laminate along second cutting lines each extending in the transverse direction of the webs between each pair of the heat-sealing lines adjacent to each other to obtain a plurality of individual pull-on diapers. The pull-on diaper made by such a conventional process is composed of a front waist region, a rear waist region and a crotch region so to define a waist-hole and a pair of leg-holes.
The process for making a pull-on diaper is disclosed, for example, in Japanese Patent Application Publication Nos. 1993-31135A, 1993-31136A and 1993-42180A.
In the case of the diaper made by the process as has exemplarily been described above, the leg-holes open laterally with respect to the waist-hole which opens in the vertical direction of the diaper as viewed from above with the waist-hole broadened with the hands. In other words, the waist-hole is out of linear alignment with the leg-holes and the crotch region lies immediately below the waist-hole. With such diaper, the wearer's toes or heels come up against transversely opposite side edges of the crotch region as the wearer's legs are let through the waist-hole and the leg-holes when the diaper is put on the wearer's body. In consequence, a much time may be taken to put the diaper on the wearer's body.
From the other viewpoint also, such diaper of the prior art is inconvenient due to the minimum width of the crotch region usually being larger than that of the wearer's crotch. Specifically, the crotch region of the diaper too bulky to be properly received by the wearer's crotch region creates a discomfortable feeling against the wearer. Furthermore, the crotch region may be irregular folded and/or formed with a plurality of irregular creases as the crotch region of the diaper is squeezed between the wearer's thighs. As a result, a body discharge absorbing function expected to the crotch region is apt to be deteriorated and body discharges may leak beyond the crotch region of the diaper.
None of the processes as have exemplarily been disclosed above includes means for folding the crotch region of the diaper and therefore the diapers made by these processes are still accompanied with the problems as have been described above.